M4 Northern Road Bridge

As part of the Western Sydney Infrastructure Plan, which supports the Western Sydney Airport and regional growth areas, DECC was appointed as the Principal Contractor to demolish the Northern Road (TNR3N) Bridge over the M4 Motorway at Orchard Hills, Sydney. This high-stakes project required precision, expertise, and rigorous planning to safely dismantle the existing bridge structure within a tight timeframe, ensuring minimal disruption to the critical transport network.

The Northern Road Bridge demolition was completed successfully within the 72-hour shutdown period, with over 11,000 tonnes of material safely removed from the site.

Demolition of Bridge Structure: Executed the removal of the entire bridge structure, including deck slabs, parapets, beams, post/pre-tensioning systems, abutments, footings, columns, precast panels, and approach slabs. This also encompassed the dismantling of pedestrian footpaths, guard rails, and redundant services while ensuring safety throughout the process.

Asbestos removal and Site Preparation: Conducted the removal of scuppers containing asbestos from the bridge deck, followed by an official clearance to confirm the site was free of hazardous materials. Site preparation also included setting up temporary hydrant points, water cannons, and installing task lighting to ensure a safe working environment during the nighttime operations.

Traffic Management and Protection Measures: Implemented extensive traffic management controls in collaboration with RMS and Lendlease to divert traffic off the M4 Motorway and onto adjacent ramps, ensuring continuous flow of vehicles while demolition was underway. The existing M4 pavement was protected using an engineered “rock mattress” to shield it from demolition debris and machinery impact.

Rock Mattress Installation: Laid down a multi-layered rock mattress constructed from recycled materials and geofabric, up to 500mm thick, to protect the underlying M4 pavement. This involved spreading and compacting layers of material to create a durable protective barrier that could withstand the force of falling debris and the movement of heavy machinery.

Execution of Demolition Strategy: Employed conventional demolition techniques using heavy machinery equipped with specialised attachments such as hydraulic hammers, rotating pulverisers, and shears to systematically dismantle the bridge. The strategy was meticulously planned to ensure efficient removal of the bridge spans while maintaining the safety of the surrounding infrastructure.